Containers to be labelled can, for example, be used as bottles for liquids such as beverages. The containers, e.g. bottles, can consist of a transparent or translucent material, for example glass, or of a translucent plastic, e.g. PET. But it is also conceivable that the containers consist of other materials and can be filled with other content.
Before the containers are supplied to the labelling machine, they are thoroughly inspected with suitable inspection devices. For example, it is envisaged that an inspection for foreign matter be performed in which the containers are inspected for unwanted foreign matter in their interiors. For example using belt conveyors, the containers are supplied to the labelling machine on its infeed side. The labelling machine, for example, has a wheel-like main star or a labelling carousel in which the containers are supplied to a labelling assembly so that the containers are provided with labels. Furthermore, prior to reaching the labelling assembly, the containers are oriented into a target position in which the containers are to be labelled so that the respective labels on the respective containers are always identically oriented. The containers are discharged, on the outfeed side, from the labelling machine or from the labelling carousel, with re-inspections then being carried out. The onward transport to the downstream inspection devices can also be performed by means of transporters or belt conveyors. For example, the containers can be checked for sufficient filling level. In the subsequent inspections, the labels are checked e.g. for correct seating, correct orientation relative to embossings or such design features and/or damages, to name but a few examples of inspections.
It is also known to arrange a first inspection unit as an orientation station and a second inspection unit e.g. as a label seating control at the labelling carousel itself.
DE 20 2005 017 180 U1 relates to a device for orienting containers and a labelling machine with such a device. The containers have at least one geometric container feature (embossing) which is to be twisted into a target position. The containers are pre-oriented with a first camera system. In the transport orientation of the container, there follows a further camera system which effects an orientation into the target position, wherein the further camera system captures a narrower area of the circumferential surface than the first camera system. Thus, DE 20 2005 017 180 U1 proposes a multi-stage, namely a three-stage, orientation for the final fine orientation, for which four cameras are provided. The first two cameras, as seen in the conveying direction, form the first orientation stage, the following third camera serves the further orientation, with the following fourth camera serving the fine orientation.
DE 20 2005 020 478 U1 deals with a label seating control of containers that were labelled on a labelling machine. The label seating control has a camera for imaging the containers equipped with labels. An optical facility is arranged between the camera and the container, said facility generating beam paths that capture labels arranged circumferentially and/or above one another, with distance in between, in a staggered manner. In doing so, only the label surfaces of interest are inspected, with all remaining surface areas of the container being disregarded. In this respect, a correct seating of the label relative to a possible embossing cannot be checked with the label seating control of DE 20 2005 020 478 U1.
DE 10 2004 005 994 A1 discloses a labelling machine. It has a device for supplying labels and a labelling assembly. The labelling assembly has a label container, a glue roller, a rotatable carrier provided with glueable removal segments, and a gripping cylinder. Thus, for example, bottles can be provided with labels, wherein the labelling machine can for example be designed as a rotary runner, a linear machine or even a horizontal runner. In the outfeed area of the labelled bottles, a label seating control facility is arranged with which the desired arrangement of the labels on the bottles is monitored. It is conceivable to check the labels for correct seating, for example relating to design features (so-called embossings) arranged on the bottles. It is also possible to check neck labels and chest labels for correct orientation to one another or also relative to the design features. In case of a change of the label seating outside a specifiable tolerance limit, the label seating control facility conveys corresponding signals for selecting a correction facility which acts upon the labelling assemblies so that a correct label seating can be achieved. Naturally, the bottles provided with an incorrectly oriented label are picked out in a rejection device which, of course, is also possible via the correspondingly generated signal of the label seating control facility.
It is known that the labelled containers are re-oriented in respect of the embossing by means of a detection system downstream of the labelling assembly (DE 10 2008 050 249 A1), to be able to perform, for the label seating control, a seating control regarding a crease-free or damaged seating and also regarding the correct orientation relative to the embossing. For example, bottles or similar containers are filled with content by means of a filling device, to then be supplied to the labelling machine. The containers are oriented (first inspection unit) in the labelling machine or before, for example relating to design features (so-called embossings), so that the labels can be applied to the container in orientation to the design features. The labelled containers are re-oriented after labelling and moved on or transported at a (second) inspection device which can be designed as a label seating control. If the label seating control detects containers with a bad or faulty label seating, a signal for rejection is generated. The rejected containers, for example bottles, are stored on a separate transporter. In this respect, for a re-orientation between the labelling assembly and the label seating control, a further detection system is provided, e.g. with the first inspection unit designed as an orientation station.
DE 10 2007 031 218 A1 deals with a device comprising a turntable which is rotatable relative to a base; drives which are arranged on the turntable, wherein each drive comprises an angle sensor; rotary plates which are arranged on the turntable, wherein each drive drives a rotary plate; and a marking track that is immovably connected with the base and revolves around the turntable. Each drive is allocated a sensor on the turntable, with which the marking track can be read out, wherein each drive comprises an electronic circuit with which the orientation regarding the base of the respective rotary plate driven by the drive can be determined from the signal of the angle sensor of the drive and the signal of the allocated sensor. In the rotary plate drive, a program is deposited in the form of a target motion sequence that specifies which rotation angle the rotary plate is to assume in respect of the base relative to the turntable at the turntable's rotation angle currently detected by the sensor. Depending on the application, a different motion sequence of the rotary plate can thus be implemented in case of a rotation of the turntable.
DE 44 41 245 A1 discloses a method for controlling labelled vessels. The control device is integrated into a labelling machine and has a laser range finder. With the laser range finder, it can be ascertained whether a container is provided with a label or not. During an active measurement interval, the laser beam emitted by the laser range finder first hits the surface of a bottle moving past and measures the bottle's distance from the range finder's fixed housing, which thus forms the constant reference point. As soon as the laser beam hits the surface of the label, there arises a sudden reduction in the currently measured distance corresponding to the thickness of the label and, where applicable, of the glue film between the bottle and the label. This sudden change in distance is detected in an evaluation unit and assessed as a criterion for the presence of a label. Correspondingly, the evaluation unit sends no signal or a good signal to a sorting device. If no label exists on the bottle, no sudden change in distance becomes detectable either, so that the evaluation unit emits an error signal to the sorting device which picks out the corresponding bottle. A main disadvantage of this is that the control facility can only ascertain whether a label exists on the bottle or not. However, it cannot be ascertained whether the label is also correctly oriented, for example relative to design features, or has creases.
DE 20 2004 021 611 U1 assumes combined label seating control facilities in which both a label seating control and a contour detection (embossings) are possible. This requires an incident light illumination for detecting both labels and transmitted images as well as a transmitted light illumination for the contour control, wherein two illumination devices emitting from different directions are used. DE 20 2004 021 611 U1 points out that the use of two illumination facilities regarding the matching of individual lighting level and individual lighting duration is problematic, which is why it is proposed to subject containers, with a single illumination facility and specially designed and adapted optical means, to both transmitted light and incident light. The optical means are for example designed as a flat plate with a bright surface or as a mirror which should be arranged at exactly adapted angles and positions relative to the beam path of the single illumination facility. Thus, labels can be checked not only in respect of crease-free or undamaged seating but, simultaneously, also in respect of the correct orientation relative to the embossing. However, this still requires a facility for detecting the embossing, said facility being combined with the label seating control.